1. Field of the Invention
This invention relates to a steering system for vehicles, and more particularly to a hydrostatic power steering system with constant volume feedback compensation.
2. Description of the Prior Art
The use of hydraulic steering cylinders to control the position of the steerable wheels on a vehicle especially off-road type vehicles, is commonplace. Normally, a mechanical linkage is employed which connects the two steering arms together in such a manner as to cause the outside wheel to generate a greater turning radius than the inside wheel. Since it is also common practice to connect the steering cylinders to extensions of the steering arms, the cylinders experience differences in piston velocities during a steering cycle. In those instances where a hydraulic feedback signal is derived from one of the working chambers of each of a pair of double-acting cylinders, any noticeable difference in piston velocities can be detrimental to the control of the vehicle. The two major problems with unequal piston velocities are a rise of internal pressure within the system and an increase in needed effort to steer the vehicle. Now a steering system which incorporates a pair of three chamber hydraulic cylinders has been invented which automatically compensates for the difference in piston velocities to maintain a constant volume feedback circuit.